Short-circuit protection with a semiconductor switch

Abstract

The invention describes a protective circuit (40a) for a traction battery (10) with a positive pole and a negative pole. The protective circuit has a semiconductor-based circuit breaker (SSCB) which is electrically connected to the positive pole of the traction battery (10). The invention also describes a power supply device (40). The invention further describes an electrically driven vehicle (1). In addition, the invention also describes a method for producing a protective circuit (40a) for a traction battery (10).

Description

[0001] Description

[0002] Short-circuit protection with semiconductor switch

[0003] The invention relates to a protective circuit for a traction battery. Furthermore, the invention relates to a power supply device. Furthermore, the invention relates to an electrically powered vehicle. Furthermore, the invention also relates to a method for producing a protective circuit for a traction battery.

[0004] Batteries for operating vehicles, also referred to below as traction batteries or traction accumulators, must be electrically charged from time to time. For this purpose, a vehicle, such as a rail vehicle, also includes power electronics. For example, in a rail vehicle, a DC / DC converter is conventionally connected between the traction battery and a so-called traction intermediate circuit.

[0005] An electrified rail vehicle with three-phase drive, as shown in FIG 1, for example, has a so-called load converter. This load converter has the traction intermediate circuit mentioned above, which is connected between the high-voltage supply from the traction power network and the three-phase drive or a traction device operated with three-phase current. Such a traction intermediate circuit usually has a direct voltage of 2 to 4 kV. In contrast, the load-dependent terminal voltage of a traction battery is usually much lower, typically < 1 kV. The DC / DC converter mentioned above is generally used to convert the electrical voltage between these different values.Other components that are indirectly connected to the traction battery via the traction intermediate circuit are a four-quadrant converter, which converts the traction power network's mains current, for example, alternating current, into direct current with a DC voltage of the traction intermediate circuit, and a drive pulse inverter, which converts the direct current of the traction intermediate circuit into multi-phase alternating current for the rail vehicle's traction motors. The traction intermediate circuit and all of these components that are electrically connected to the traction intermediate circuit, as well as the electrical connecting lines between them, can be damaged and subject to short circuits.

[0006] Vehicles with traction batteries therefore often include an overcurrent protection element, for example a so-called fast-acting fuse, to protect the traction battery against short-circuits. Such fuses are shown in FIG. 2. A rail vehicle usually has only one central traction intermediate circuit per traction motor group, i.e., per bogie. A short circuit in such a central traction intermediate circuit or a simple earth fault in vehicles with an earthed traction intermediate circuit (corresponding to an earth short circuit) therefore leads to the simultaneous triggering of all overcurrent protection elements or fuses for the relevant traction motor group.

[0007] Such non-selective protective reactions resulting from short circuits in the traction intermediate circuit lead to a loss of vehicle availability that can no longer be ignored, with the associated disadvantages for the vehicle operator, such as operational interruptions and costs for replacing spare parts.

[0008] Conventional mechanical DC high-speed fuse switches have the following disadvantages:

[0009] - they switch too slowly, which leads to very high switching overcurrents in the circuits concerned when the inductance values ​​are low,

[0010] DC high-speed circuit breakers are large and heavy. Such mechanical high-speed circuit breakers of the UR10 / UR15 type are described in https: / / www.se-online.com / wp-content / uploads / 2021 / 10 / -SG104136BDE_C04_Brochure_Circuit-breaker-DC_UR10-15_08.20.pdf. UR10 and UR15 are current-limiting, single-pole, naturally cooled, bidirectional DC circuit breakers with trip-free operation, electromagnetic blow-off device, electrical control circuits, and direct, instantaneous overcurrent release.

[0011] Fuses based on the principle of pyrotechnic separation, so-called pyrofuses, have the following disadvantages:

[0012] - if such a fuse is triggered, it can no longer be reset,

[0013] - the use of explosives can cause unforeseeable consequences.

[0014] Furthermore, SSCB single switches (SSCB is an abbreviation for Solid State Circuit Breaker) are conventionally used for stationary industrial applications, but not for traction batteries.

[0015] The object is therefore to provide a protective circuit for a battery-based power supply of a vehicle which at least partially overcomes the above-mentioned problems of battery-based power supply devices for vehicles with conventional circuit breakers.

[0016] This object is achieved by a protective circuit for a traction accumulator according to patent claim 1, a power supply device according to patent claim 12, an electrically driven vehicle according to patent claim 13 and a method for producing a protective circuit for a traction accumulator according to patent claim 14.

[0017] The protective circuit according to the invention for a traction accumulator has a semiconductor-based circuit breaker. The traction accumulator has a positive pole and a negative pole. The semiconductor-based circuit breaker is electrically connected to the positive pole of the traction accumulator. It should be noted that a conventional one-time fuse, which preferably comprises a melting fuse, is preferably arranged between the positive pole of the traction accumulator and the semiconductor-based circuit breaker. This one-time fuse is usually already assigned to the traction accumulator or is part of this traction accumulator. The traction accumulator is preferably designed for use in a rail vehicle.A semiconductor-based circuit breaker is an electronic circuit breaker whose switching behavior to prevent overcurrents or overvoltages is based on the specific electronic properties of different semiconductor materials, especially differently doped semiconductor materials. A semiconductor-based circuit breaker comprises semiconductor-based components, preferably diodes, especially inverse diodes, and transistors.

[0018] Such a protective circuit with a semiconductor-based circuit breaker has the advantage over a protective circuit with a one-time fuse that the semiconductor-based circuit breaker can be used multiple times without having to be replaced. In particular, when the circuit breaker is used in combination with a one-time fuse, i.e. is connected in series with such a one-time fuse, the flexibility and low maintenance requirements of the semiconductor-based circuit breaker can be combined with the high safety and reliability of the one-time fuse. In particular, in most events involving the occurrence of an overcurrent, activation of the one-time fuse and the subsequent necessary maintenance process, which includes, for example, replacing the one-time fuse, can be avoided. Furthermore, such a semiconductor-based circuit breaker has the advantage of a high shutdown speed.Thus, when the semiconductor-based circuit breaker according to the invention is combined with a one-time fuse, a "burnout" of the one-time fuse is advantageously avoided, even in the case of low-inductance short circuits, even when a super-fast-acting fuse is used as the one-time fuse, since the semiconductor-based circuit breaker switches in time before the one-time fuse reacts. Furthermore, the rapid switching of the semiconductor-based circuit breaker can also achieve a reduction in the amplitude of a short-circuit current.

[0019] The protective circuit according to the invention forms a "quasi-short-circuit-proof traction battery" with the traction accumulator. This is because the semiconductor-based protective switch can preferably be switched and reset as often as required in the event of a short circuit in the traction intermediate circuit.

[0020] The power supply device according to the invention has a traction accumulator with a positive pole and a negative pole. Furthermore, the power supply device according to the invention comprises a protective circuit according to the invention, the semiconductor-based circuit breaker of which is electrically connected to the positive pole of the traction accumulator. Furthermore, the power supply device according to the invention comprises a DC-based traction intermediate circuit, which is electrically connected to the protective circuit and the traction accumulator. Furthermore, the power supply device according to the invention comprises a drive pulse inverter for transforming the DC current of the traction intermediate circuit into three-phase AC current for traction.The power supply device according to the invention preferably comprises a so-called traction converter, also referred to as a load converter, which has the mentioned components, in particular the DC-based traction intermediate circuit and the drive pulse inverter as well as the protective circuit.

[0021] A traction accumulator is understood to be a rechargeable electrical energy store which is used in conjunction with the power supply device according to the invention for the mains-independent supply of traction devices, in particular the traction motors, and preferably the other electrical functional units of a rail vehicle. Such a traction accumulator has a large number of accumulator cells connected in parallel and in series and is designed as a high-voltage battery and for the provision of strong electrical currents in order to be able to provide sufficient power for the traction of a vehicle, in particular a rail vehicle. Electrical voltages of 400 volts to 1000 volts are typical nominal battery voltages in order to be able to drive heavy vehicles, such as rail vehicles.A traction accumulator typically also features a so-called battery management system, which prevents overloading of individual cells during energy extraction. The traction devices comprise electric motors for driving the drive wheels of the rail vehicle. To supply the traction devices with electrical current at a suitable electrical voltage, the power supply device comprises the aforementioned traction intermediate circuit. Such a traction intermediate circuit is generally part of the aforementioned load converter, which performs current / voltage conversion between the current from the traction power network or the current from a traction accumulator and the rail vehicle's components.

[0022] As already mentioned, the traction intermediate circuit is connected between the high-voltage supply from the traction power network and the three-phase drive or a traction device operated with three-phase current. Such a traction intermediate circuit usually has a direct voltage of 2 to 4 kV and supplies direct voltage. To generate the direct voltage, the power electronics of a rail vehicle also include a so-called four-quadrant divider, which is connected between the overhead line network and the traction intermediate circuit and can also be included in the load converter. The traction motors of the traction devices are usually operated with three-phase current, while the traction current is taken from the traction power network as alternating current with a high electrical voltage, for example 15 kV or 25 kV.

[0023] The drive pulse inverter of the power supply device according to the invention is part of the load current converter and converts the direct current of the traction intermediate circuit into the three-phase current required by one traction motor or by several traction motors of the traction devices. To transmit the three-phase current to the traction motors, the power supply device according to the invention preferably also has a three-phase cable system for supplying one or more traction motors, which is electrically connected to the drive pulse inverter. In traction operation, the drive pulse inverter converts the direct voltage of the intermediate circuit into a three-phase voltage of variable amplitude, frequency and phase for a traction motor, in particular a three-phase machine (asynchronous or synchronous motor), and regulates this with regard to speed and torque.

[0024] Such a drive pulse inverter can be designed for a single traction motor. In this variant, also known as individual axle feed, a separate drive pulse inverter is provided for each traction motor. This arrangement has the advantage that individual traction motors or their torque and wheel-rail slip can be controlled or regulated individually. In an alternative variant, a common drive pulse inverter can be provided for several traction motors or for all traction motors. In this variant, also known as group feed, the power of the drive pulse inverter is selected to be so high that several traction motors, preferably all traction motors, are controlled in parallel via a common drive pulse inverter.Accordingly, the traction intermediate circuit can also be designed as a common traction intermediate circuit for several traction motors or several traction intermediate circuits, each for individual traction motors, can be included in the load current converter or the power supply device according to the invention.

[0025] The power supply device according to the invention shares the advantages of the protective circuit according to the invention.

[0026] The electrically powered vehicle according to the invention, preferably a rail vehicle, has a traction device and the power supply device according to the invention for supplying energy to the traction device. The electrically powered vehicle according to the invention shares the advantages of the power supply device according to the invention.

[0027] In the method according to the invention for producing a protective circuit for a traction battery, which has a positive pole and a negative pole, a semiconductor-based protective switch is produced. Furthermore, the semiconductor-based protective switch is electrically connected to the positive pole of the traction battery. Thus, according to the invention, a protective circuit for a traction battery is advantageously created with a fuse against overvoltages and excessive currents, which can be used as often as desired and requires less maintenance than conventional fuses.

[0028] The dependent claims and the following description each contain particularly advantageous embodiments and developments of the invention. In particular, the claims of one claim category can also be developed analogously to the dependent claims of another claim category and their description parts. Furthermore, within the scope of the invention, the various features of different embodiments and claims can also be combined to form new embodiments. In one embodiment of the protective circuit according to the invention for a traction battery, the semiconductor-based protective switch comprises a preferably fast current measuring unit. Advantageously, the current measuring unit can be used to measure a sharp current increase and in particular a short-circuit current through the semiconductor-based protective switch.Rapid measurement of a current rise allows for rapid interruption of the power supply, thus achieving good selectivity with respect to a super-fast-acting fuse, even in the case of low-inductance short circuits. "Rapid" in this case means that a current rise can be measured in time before a one-time fuse reacts to the current rise.

[0029] Particularly preferably, the semiconductor-based circuit breaker comprises an evaluation and control component with which the circuit breaker can be switched into a blocking state or a conducting state depending on a measurement result of the current measuring unit.

[0030] The semiconductor-based circuit breaker is also preferably cooled using a cooling plate. The cooling plate is preferably designed as a common cooling plate for the circuit breaker and the additional components, in particular the current measuring unit and the evaluation and control components. The overall design is simplified by arranging them on a common cooling plate.

[0031] Furthermore, the circuit breaker of the protective circuit according to the invention preferably comprises additional circuitry. The additional circuitry is designed to limit voltage peaks and preferably comprises a so-called snubber capacitor or a varistor. Rapid and strong voltage increases are advantageously avoided, thereby improving the durability of the circuit breaker.

[0032] In one embodiment of the protective circuit according to the invention for a traction battery, the semiconductor-based protective switch comprises an input and an output, and the input of the semiconductor-based protective switch is preferably electrically connected to the positive pole of the traction battery. The "input" is understood to be the connection of the semiconductor-based protective switch into which a direct electrical current flows, and the "output" is understood to be the connection of the semiconductor-based protective switch from which a direct electrical current flows. As explained in detail later, the input and output of the semiconductor-based protective switch can be flexibly wired depending on the specific requirements.

[0033] The semiconductor-based circuit breaker preferably comprises a plurality of parallel individual switches. Advantageously, a plurality of individual switches can handle a higher electrical power than a single switch. Furthermore, different sources and consumers can be electrically connected using different individual switches. This procedure is advantageous in a modular design of a power supply device with a plurality of energy storage devices connected in parallel and / or a plurality of electrical consumers connected in parallel. The energy storage devices connected in parallel preferably comprise modules connected in parallel, also referred to as battery modules or accumulator modules. The electrical consumers can in particular comprise traction intermediate circuits connected in parallel and traction devices connected thereto, i.e. drive motors.

[0034] Therefore, in a preferred variant of the protective circuit according to the invention, the traction accumulator preferably comprises a plurality of such parallel (battery) modules, at least two of which are electrically connected to different individual switches of the semiconductor-based protective switch. An accumulator usually comprises a so-called battery pack. The battery pack includes a battery management system with which the operation of the accumulator is monitored and regulated. The battery pack usually has a plurality of battery modules, also referred to as modules for short, which each comprise a housing for a plurality of battery cells. A battery module comprises a series-parallel combination of battery cells. The modular design enables flexible scaling of an accumulator, i.e. flexible adaptation to a desired energy storage capacity.Since the protective switch of the protective circuit according to the invention preferably comprises a plurality of parallel individual switches, these can be electrically connected individually to different modules of the traction accumulator, so that individual modules can be selectively protected and, if necessary, unaffected modules can continue to operate even in the event of a short circuit.

[0035] If the circuit breaker comprises a plurality of individual switches, the individual switches preferably each have such additional circuitry. The individual switches are preferably arranged on a common heat sink, which simplifies the design compared to separate cooling of individual components.

[0036] In one embodiment of the traction accumulator according to the invention, each of the semiconductor-based circuit breakers comprises a preferably fast current measuring unit. Advantageously, the current measuring unit can be used to individually measure a sharp current increase, and in particular a short-circuit current, through the individual switch for each phase. "Fast" in this case means that the current measuring unit can measure a current increase in time before a one-time fuse reacts to the current increase.

[0037] Particularly preferably, each of the individual switches comprises an evaluation and control component with which the respective individual switch can be switched to a blocking state or a conducting state depending on a measurement result of the current measuring unit. Advantageously, individual modules of the traction accumulator or individual phases can be selectively switched off if a short circuit has been detected, while all other modules or phases can continue to operate.

[0038] Most preferably, each of the parallel modules is electrically connected to a different individual switch of the semiconductor-based circuit breaker. Advantageously, each of the modules can be assigned a separate phase. Defective modules can advantageously be controlled or switched off individually and specifically, while the functionality of the remaining modules is maintained.

[0039] In a variant of the protective circuit according to the invention, the output of the circuit breaker has a plurality of parallel connections or phases, each of which is electrically connected to at least one of the parallel individual switches. Advantageously, a plurality of different electrical loads can be supplied with power in parallel. Individual circuit breakers can be assigned to independent traction intermediate circuits and loads.

[0040] Likewise, the number of connections or phases of the circuit breaker input is preferably smaller than the number of parallel individual switches. In this variant, the phases or connections of several individual switches are bundled in order to supply one or more consumers with particularly high current or energy requirements. It may also happen that the traction battery has fewer modules than the circuit breaker individual switch. Even then, it may be sensible to provide a smaller number of connections at the input than the number of individual switches.

[0041] Preferably, the output of the circuit breaker has exactly one connection or phase, which is electrically connected to the plurality of parallel individual switches. In this variant, the plurality of circuit breakers are bundled or combined into a single phase in order to supply a single energy consumer with a particularly high energy consumption. This variant can be used when connecting a traction accumulator with exactly one single traction intermediate circuit. This variant is advantageous in that the chip area required by the circuit breaker is utilized as optimally as possible.

[0042] Preferably, the circuit breaker input has a number of parallel connections, and the number of input connections is equal to the number of parallel individual switches of the semiconductor-based circuit breaker. In this variant, all individual switches are controlled via a separate connection or a separate phase. In such a configuration, the number of traction battery modules generally corresponds to the number of individual switches. The entire switching capacity of the circuit breaker is advantageously utilized with maximum selectivity of the modules.

[0043] In one variant of the protective circuit according to the invention, the input of the semiconductor-based protective switch has a number of parallel connections and the number of connections of the input is smaller than the number of parallel individual switches of the semiconductor-based protective switch. In this variant, not all individual switches are controlled separately. As a rule, with such a circuit the number of modules of the traction accumulator is smaller than the number of parallel individual switches of the semiconductor-based protective switch. If necessary, a module can be connected to several individual switches, so that the current capacity per module is increased compared to connecting an individual module to only one individual switch.

[0044] In a special variant of the protective circuit according to the invention for a traction battery, the input has exactly one connection. In this variant, the semiconductor-based protective switch is controlled like a single monolithic switch with maximum load capacity or current capacity for one phase at the input. If the protective switch also has only one phase at its output, to which several or even all individual switches are combined, it also behaves like a single switch at its output. Alternatively, it is also conceivable to distribute the current at the output among several consumers, for example to control several traction intermediate circuits.

[0045] In one variant of the protective circuit according to the invention for a traction battery, the number of connections is equal to the number of parallel modules of the traction battery. In this variant, all connections are connected to modules of the traction battery. However, the number of connections does not have to correspond to the number of individual switches. For example, several switches can be connected in parallel to one connection. This can therefore result in several independent switches, each comprising a plurality of switches combined in parallel, with increased power. In the latter case, the number of connections is smaller than the number of parallel individual switches.

[0046] In a particularly specific embodiment of the protective circuit according to the invention, the protective switch comprises a plurality of individual switches, preferably six parallel individual switches. Each of the preferably six individual switches comprises a transistor and an inverse diode connected in parallel. Furthermore, each individual switch comprises additional circuitry. The additional circuitry is designed to limit voltage peaks and is preferably implemented by a so-called snubber capacitor or a varistor. The individual switches are preferably arranged on a common heat sink. Furthermore, the protective switch preferably comprises a fast current measuring unit and an evaluation and control component. The protective switch is preferably cooled by means of a cooling plate. In order to be able to switch off each phase individually, the current of each individual switch is evaluated and each individual switch can be controlled individually.The additional circuitry advantageously prevents the occurrence of potentially damaging voltage spikes. The fast current measuring unit and a suitable evaluation and control component enable a particularly well-adapted and rapid response of the circuit breaker to a potentially damaging current, before a one-time fuse reacts.

[0047] In one embodiment of the method according to the invention for producing a protective circuit for a traction battery, a semiconductor-based protective switch for a traction battery is produced, which has a plurality of modules, i.e., energy storage modules, preferably six modules. The semiconductor-based protective switch is designed with the plurality of individual switches connected in parallel and with an input and an output.

[0048] The positive poles of the traction battery modules are then electrically connected to the input of the semiconductor-based circuit breaker. The individual switches of the semiconductor-based circuit breaker are each electrically connected to the various modules of the traction battery.

[0049] Furthermore, the output of the semiconductor-based circuit breaker is connected to one or more traction intermediate circuits, wherein preferably all individual switches are combined to a predetermined number of traction intermediate circuits, preferably to a single traction intermediate circuit, or optionally fed individually to the traction intermediate circuits if their number corresponds to the number of individual switches. Advantageously, a specific configuration of the protective circuit can be implemented depending on a specific application. The invention is explained in more detail below with reference to the attached figures using exemplary embodiments. They show:

[0050] FIG 1 is a schematic representation of a rail vehicle with a conventional power supply device with a traction accumulator,

[0051] FIG 2 is a schematic diagram of a conventional power supply circuit with current fuses,

[0052] FIG 3 is a schematic representation of a power supply device according to an embodiment of the invention,

[0053] FIG 4 shows a detailed representation of a circuit breaker of the power supply device already shown in FIG 3,

[0054] FIG 5 shows a protection circuit with a circuit breaker with a multi-phase circuit at its input and its output,

[0055] FIG 6 a protection circuit with a circuit breaker with a multi-phase circuit of its input and a single-phase circuit of its output,

[0056] FIG 7 a protection circuit with a circuit breaker with a single-phase circuit of its input and its output,

[0057] FIG 8 a protection circuit with a circuit breaker with a two-phase circuit of its input and its output,

[0058] FIG 9 is an enlarged view of an individual switch of a protective switch, FIG 10 is a flow chart illustrating a method for producing a protective circuit for a traction battery according to an embodiment of the invention.

[0059] FIG 1 shows a schematic representation of an electrically powered vehicle 1, in this case a conventional electrified rail vehicle 1, with a traction battery 10. The electrified rail vehicle 1 comprises a pantograph 2 for supplying electrical energy from the AC traction power network, which pantograph is electrically connected to a main transformer 4 via a circuit breaker 3. The main transformer 4 transforms the high voltage of the AC traction power network into a lower AC voltage, which is then converted via a four-quadrant divider 5 into an intermediate circuit DC voltage of approximately 2 to 4 kV for a traction intermediate circuit ZK. Traction devices 8, i.e. in particular traction motors, are supplied with three-phase current from the traction intermediate circuit ZK via pulse-controlled inverters, in particular drive pulse-controlled inverters 7.Furthermore, there is also a direct current connection via a DC-DC converter 9 between the traction intermediate circuit ZK and the traction battery 10. The traction intermediate circuit ZK is also electrically connected to a three-phase on-board network (not shown) via an auxiliary converter (not shown).

[0060] FIG. 2 shows a schematic representation of a conventional power supply circuit 30 with current fuses Fl. 1, Fl. 2 as single-blow fuses. The power supply circuit 30 comprises a traction accumulator 10 with a positive pole and a negative pole. At both poles, the traction accumulator 10 has a single-blow fuse Fl. 1, Fl. 2, which, however, can no longer be reset to its original state after an overcurrent or a short circuit KS and must therefore be replaced. Also part of the power supply circuit 30 is a traction intermediate circuit ZK (shown in the center) with a capacitance Czk and a drive pulse inverter 7, which converts the direct current of the traction intermediate circuit ZK into three-phase current. The three-phase current (symbolized by a "3" in FIG. 2) is used for traction by a traction device, in this case an electric motor 8.The power supply circuit 30 is electrically connected to earth via the rails S. This means that the negative pole of the traction battery 10 is earthed.

[0061] 3 shows a schematic representation of a power supply device 40 according to an exemplary embodiment of the invention. The power supply device 40 shown in FIG. 3 differs from the conventional power supply circuit 30 shown in FIG. 3 in that it additionally has the protective circuit 40a according to the invention with a semiconductor-based protective switch SSCB. The protective circuit SSCB is electrically connected to a disposable fuse Fl. 1, i.e. one of the two disposable fuses Fl. 1, Fl. 2 on the side of the positive pole of the traction battery 10 (shown in FIG. 3 on the upper side of the representation). The protective switch SSCB reacts to an increase in a short-circuit current and thereby prevents both an excessive electrical current and the blowing of the disposable fuse Fl. 1, so that it remains intact even in the event of a short circuit.The protection circuit 40a is arranged on a load converter LSR. The load converter comprises further electronic components, such as the traction intermediate circuit ZK shown in FIG. 3 and the drive pulse inverter 7 shown in FIG. 3.

[0062] In FIG. 4, in addition to the schematic representation of a power supply device 40 according to an embodiment of the invention already known from FIG. 3, a detailed representation of the protective circuit 40a with the semiconductor-based protective switch SSCB and the traction accumulator 10 of the power supply device 40 already shown in FIG. 3 is illustrated in the lower section.

[0063] The traction battery 10 has a plurality of modules M1, M6 connected in parallel. The semiconductor-based circuit breaker SSCB of the protection circuit 40a has a plurality of individual circuit breakers SI, S2, ..., S6, which are electrically connected to the modules M1, ..., M6 via individual phases PI, ..., P6 and are respectively assigned to them. Each of the individual modules M1, ..., M6 of the traction battery 10 can thus be protected separately, or each of the individual phases PI, ..., P6 can be interrupted individually. If a short circuit occurs in the traction intermediate circuit ZK, for example due to a ground short circuit in the motor 8, each individual circuit breaker SI, S2, ..., S6 switches so quickly that the short-circuit currents do not rise so quickly and the fuses in the battery branches do not trigger.In addition, the very rapid shutdown reduces the level of the short-circuit current compared to an arrangement with only a single-use fuse Fl.l, for example a fusible link. After the fault has been rectified, the traction battery 10 or one of the modules Ml, M2, ..., M6 can be reconnected via the protective switch SSCB or one of the individual switches SI, S2, ..., S6. This creates a short-circuit-proof power supply circuit or power supply device 40, ie a short circuit can occur as often as desired without the fuse blowing or damage to the traction battery 10. The protective switch SSCB can therefore selectively switch off individual phases that are affected by a defect.

[0064] FIG. 5 shows a schematic representation of a protective circuit 40a with a multi-phase circuit of a protective switch SSCB at its input and its output according to an exemplary embodiment of the invention. In the circuit shown in FIG. 5, all individual switches SI, S2, ..., S6 are connected independently of one another. The number of connections of input E and the number of connections of output O of the protective switch SSCB corresponds to the number of individual switches SI, S2, ..., S6. The individual SSCB switches SI, S2, ..., S6 can, for example, be assigned to independent intermediate circuits ZK and different loads.

[0065] FIG. 6 shows a schematic representation of a protective circuit 40a with a protective switch SSCB with a multi-phase circuit at its input E and a single-phase circuit at its output O. Such a circuit can be used, for example, for the power supply device 40 shown in FIG. 3 and FIG. 4, wherein all 6 modules Ml, M2, . . . , M6 of the traction battery 10 are connected to a single intermediate circuit ZK. Selective switching off of individual phases or individual modules Ml, M2, . . . , M6 is possible here. In this variant, the chip area of ​​the protective switch SSCB is used as optimally as possible.

[0066] FIG. 7 shows a schematic representation of a protective circuit 40a comprising a protective switch SSCB with a single-phase circuit at its input E and a single-phase circuit at its output O. This circuit ensures that the effect of the plurality of individual switches SI, S2, ..., S6 of the protective switch SSCB corresponds to the effect of a single individual switch with a high current capacity.

[0067] FIG. 8 shows a schematic representation of a protection circuit 40a comprising a circuit breaker SSCB with a two-phase connection of its input E and a two-phase connection of its output O. In the configuration shown in FIG. 8, the external effect corresponds to two independent parallel "half-size" switches.

[0068] FIG. 9 shows a protective circuit 40a with a protective switch SSCB with the circuitry shown in FIG. 5, wherein one of the six parallel individual switches SI, S2, ..., S6, the sixth individual switch S6, is shown in detail. Each of the six individual switches SI, S2, S6 comprises a transistor T and an inverse diode D connected in parallel thereto. Furthermore, each individual switch comprises additional circuitry Z. The additional circuitry Z is designed to limit voltage peaks and can be implemented, for example, by a so-called snubber capacitor or a varistor. The individual switches SI, S2, ..., S6 are arranged on a common heat sink (not shown). Furthermore, the protective switch SSCB comprises a fast current measuring unit (not shown) and an evaluation and control component (not shown).The SSCB circuit breaker is cooled by means of a cooling plate on which the SSCB circuit breaker is mounted. To be able to switch off each phase individually, the current of each individual switch SI, S2, ..., S6 is evaluated, and each individual switch can be controlled individually.

[0069] The arrangement is interface-compatible with the existing power converter kit. Such a power converter kit includes semiconductor modules with identical dimensions, such as the SSCB circuit breaker and many other components, from which, for example, a four-quadrant converter or pulse-controlled inverter can be assembled, as well as control technology. These components or modules are then installed together in a power converter cabinet as part of an LSR load converter. The arrangement is interface-compatible with the dimensions of the mounting module unit, the cooling connections, and the control interface of the load converter.

[0070] FIG 10 shows a flow chart 1000 which illustrates a method for producing a protective circuit for a traction accumulator according to an embodiment of the invention.

[0071] In step 10.1 of the method according to the invention, a semiconductor-based circuit breaker SSCB is manufactured for a traction battery 10, which in this exemplary embodiment has six modules M1, M2, ..., M6. The semiconductor-based circuit breaker SSCB is formed with six individual switches S1, S2, ..., S6 connected in parallel and with an input E and an output O. Such a circuit breaker SSCB is shown, for example, in FIG. 6.

[0072] Subsequently, in step 10.II, the modules of the traction battery 10 are electrically connected on the positive pole side to input E of the semiconductor-based circuit breaker SSCB. Here, the individual switches SI, S2, ..., S6 of the semiconductor-based circuit breaker SSCB are each electrically connected to the different modules M1, M2, ..., M6 of the traction battery 10.

[0073] In step 10.III, the output 0 of the semiconductor-based circuit breaker SSCB is connected to a traction intermediate circuit ZK. In the embodiment illustrated in FIG. 10, all individual switches SI, S2, ..., S6 are combined into a single traction intermediate circuit ZK. The protective circuit 40a thus formed corresponds to the protective circuit 40a illustrated in FIG. 6.

[0074] Finally, it is emphasized once again that the methods and devices described above are merely preferred embodiments of the invention and that the invention may be varied by those skilled in the art without departing from the scope of the invention, as defined by the claims. For the sake of completeness, it is also emphasized that the use of the indefinite articles "a" or "an" does not exclude the possibility that the features in question may be present multiple times. Likewise, the term "unit" does not exclude the possibility that it consists of multiple components, which may also be spatially distributed. Regardless of the grammatical gender of a particular term, persons with male, female, or other gender identities are included.

Claims

Patent claims 1. Protection circuit (40a) for a traction accumulator (10) which comprises a positive pole and a negative pole, comprising a semiconductor-based protective switch (SSCB) electrically connected to the positive pole of the traction accumulator (10).

2. Protection circuit according to claim 1, wherein the semiconductor-based protective switch (SSCB) comprises an input (E) and an output (O), and preferably the input (E) of the semiconductor-based protective switch (SSCB) is electrically connected to the positive pole of the traction accumulator (10).

3. Protection circuit according to claim 2, wherein the semiconductor-based protection switch (SSCB) comprises a plurality of parallel individual switches (SI, S2, ..., S6).

4. Protection circuit according to claim 3, comprising a plurality of parallel modules (Ml, M2, ..., M6), of which at least two parallel modules are electrically connected to different individual switches (SI, S2, ..., S6) of the semiconductor-based protective switch (SSCB).

5. Protection circuit according to claim 4, wherein each of the parallel modules (Ml, M2, ..., M6) is electrically connected to a different individual switch (SI, S2, ..., S6) of the semiconductor-based protection switch (SSCB).

6. Protection circuit according to one of claims 3 to 5, wherein the output (0) has a plurality of parallel terminals (PI, P2, ..., P6), each of which is electrically connected to at least one of the parallel individual switches (SI, S2, ..., S6).

7. Protection circuit according to claim 6, wherein the number of parallel terminals (Pl, P2, P6) is smaller than the number of parallel individual switches (S1, S2, S6).

8. Protection circuit according to claim 7, wherein the output (0) has exactly one terminal (PI) which is electrically connected to the plurality of parallel individual switches (SI, S2, ..., S6).

9. Protection circuit according to one of claims 3 to 8, wherein the input (E) has a plurality of parallel terminals (P1, P2, P6) and the number of terminals (P1, P2, ..., P6) of the input (E) is equal to the number of parallel individual switches (SI, S2, ..., S6) of the semiconductor-based circuit breaker (SSCB).

10. Protection circuit according to one of claims 3 to 8, wherein the input (E) has a plurality of parallel terminals (PI, P2) and the number of terminals (PI, P2) of the input (E) is smaller than the number of parallel individual switches (SI, S2, ..., S6) of the semiconductor-based protective switch (SSCB).

11. Protection circuit according to one of claims 3 to 10, wherein the input (E) has a plurality of parallel terminals (P1, P2, ..., P6) and the number of terminals (P1, P2, ..., P6) is equal to the number of parallel modules (M1, M2, ..., M6) of the traction accumulator (10).

12. Power supply device (40) comprising: - a traction accumulator (10) with a positive pole and a negative pole, - a protective circuit (40a) according to one of the preceding claims, - a DC-based traction intermediate circuit (ZK) connected to the traction accumulator (10) and the protection circuit (10a) is electrically connected, - a drive pulse inverter (7) for transforming the direct current of the traction intermediate circuit (ZK) into three-phase alternating current for traction.

13. Electrically powered vehicle (1) comprising: - a traction device (8) , - a power supply device (40) according to claim 12 for supplying energy to the traction device (8).

14. A method for producing a protective circuit (40a) for a traction accumulator (10) with a positive pole and a negative pole, comprising the steps: - Manufacturing a semiconductor circuit breaker (SSCB), - electrically connecting the semiconductor circuit breaker (SSCB) to the positive pole of the traction battery (10).

Images